Design Of High Sensitivity Switch Type Hall Sensor Chip

With the development of sensor technology,switch type hall sensor chips have been widely used in industrial equipment and household appliances.Because of the high sensitivity of the switch type hall sensor chip,it can be used in weak magnetic field.However,due to the factors such as the offset voltage of the hall plate and the power supply noise,the sensitivity characteristics of the switch type hall sensor chip are limited.Therefore,it is of great theoretical significance and engineering application value to study the suppression methods of offset voltage and noise,and design a high sensitivity switch type hall sensor chip.Based on the analysis of hall plate offset voltage source,in order to suppress the offset voltage,the hall plate was designed by the rotating current method,and the hall plate model was simulated and analyzed by Verilog-a language.By studying the method for achieving high sensitivity,a block diagram of the hall signal processing circuit is proposed.The hysteresis comparator using a cascade structure of a differential amplifier circuit and a positive feedback amplifier circuit is designed,which not only set the low threshold,but also improves the sensitivity of the chip.At the same time,the output signal of the hysteresis comparator is processed by the shaping circuit,and the output level with fast jump is obtained.In order to suppress the power supply noise and meet the wide input range of power supply voltage,the regulator circuit with high power supply rejection ratio and low linear adjustment rate is proposed.Through the design of the trimming circuit for the hysteresis comparator and the bias circuit,it can adjust the bias voltage.At the same time,the threshold voltage can be adjusted in a certain range,then achieve the suppression of the input offset voltage,and guarantee reliability of the chip high sensitivity.Based on Dongbu HiTek 0.18um BCD simulation library file,the whole circuit was simulated with Hspice software to verify the feasibility of theoretical analysis and design method.Finally,the chip layout is designed,DRC and LVS verification is completed.The designed switch type hall sensor chip can correctly respond to the weak magnetic field,and its sensitivity characteristic is improved compared with the traditional value.At the same time,the wide input range of power supply voltage and the high frequency of applicable magnetic field make the chip become more applicable.